Clusters in intense laser pulses

We discuss the response of clusters subject to intense laser fields in the framework of a time dependent density functional approach which allows a fu lly non adiabatic treatment of both electronic and ionic degrees of freedom . Most results have been obtained for simple metal clusters. We discuss in this case the importance of the plasmon resonance in the electronic respons e. We also consider the impact of ionic motion on the ionization of these m etal clusters. We show in particular that for long enough pulses, ionic exp ansion can drive the system into resonance with the electronic plasmon reso nance, which leads to a strongly enhanced ionization. We finally consider t he case of hydrogen clusters, in relation to recent experiments on fusion f rom irradiated deuterium clusters. We analyze the response of small hydroge n clusters to moderately intense lasers with intensities up to typically a few 10(15) W cm(-2). Ionic degrees of freedom seem to be here even more imp ortant.